On 19/7/29 06:51, Dave Chinner wrote: > On Fri, Jul 26, 2019 at 09:12:07AM +0800, Joseph Qi wrote: >> >> >> On 19/7/26 05:20, Andreas Dilger wrote: >>> >>>> On Jul 23, 2019, at 5:17 AM, Joseph Qi <jiangqi903@xxxxxxxxx> wrote: >>>> >>>> Hi Ted & Jan, >>>> Could you please give your valuable comments? >>> >>> It seems like the original patches should be reverted? There is no data >> >> From my test result, yes. >> I've also tested libaio with iodepth 16, it behaves the same. Here is the test >> data for libaio 4k randrw: >> >> ------------------------------------------------------------------------------------------- >> w/ parallel dio reads | READ 78313KB/s, 19578, 1698.70us | WRITE 78313KB/s, 19578, 4837.60us >> ------------------------------------------------------------------------------------------- >> w/o parallel dio reads| READ 387774KB/s, 96943, 1009.73us | WRITE 387656KB/s，96914, 308.87us >> ------------------------------------------------------------------------------------------- >> >> Since this commit went into upstream long time ago，to be precise, Linux >> 4.9, I wonder if someone else has also observed this regression, or >> anything I missed? > > I suspect that the second part of this set of mods that Jan had > planned to do (on the write side to use shared locking as well) > did not happen and so the DIO writes are serialising the workload. > Thanks for the inputs, Dave. Hi Jan, Could you please confirm this? If so, should we revert this commit at present? Thanks, Joseph
